Taking a cross-disciplinary approach to the subject, this book explores THz astrophysics and the technologies that make this rapidly evolving field possible. It provides readers with both the background science and technology to interpret THz observations and design, build, and deploy THz astronomical instrumentation. The first four chapters discuss the origin and interpretation of THz light in astrophysical sources. The remaining five chapters present an overview of the technologies used to collect and detect THz light.